Some communication systems transmit data from a transmitter to a receiver over multiple communication channels, using multiple transmit antennas and multiple receive antennas. Multiple-channel transmission is used, for example, in spatial multiplexing schemes that achieve high throughput and in spatial diversity schemes that achieve high resilience against channel fading and multipath. These schemes are often referred to collectively as Multiple-Input Multiple-Output (MIMO) schemes.
MIMO schemes are used, for example, in Evolved Universal Terrestrial Radio Access (E-UTRA) systems, also referred to as Long Term Evolution (LTE) systems. The Third Generation Partnership Project (3GPP) E-UTRA standards specify MIMO schemes for use by E-UTRA User Equipment (UE) and base stations (eNodeB). These schemes are described, for example, in 3GPP Technical Specification 36.211, entitled “Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 8),” (3GPP TS 36.211), version 8.9.0, December, 2009; and in 3GPP Technical Specification 36.212, entitled “Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplexing and Channel Coding (Release 8),” (3GPP TS 36.212), version 8.8.0, December 2009, which are incorporated herein by reference. In particular, section 5.1.4 of the TS 36.212 specification describes rate matching for LTE transport channels.
The 3GPP is currently in the process of specifying an extension of the E-UTRA specification, which is referred to as LTE-Advanced (LTE-A). The evolving LTE specifications contemplate MIMO transmission using up to eight transmit antenna ports. LTE-A schemes are described, for example, in 3GPP Technical Report TR 36.814, entitled “Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Further advancements for E-UTRA physical layer aspects (Release 9),” (3GPP TR 814), version 9.0.0, March, 2010, which is incorporated herein by reference. Chapter 7 of this technical report describes downlink MIMO transmission schemes for use in LTE-A systems.
The description above is presented as a general overview of related art in this field and should not be construed as an admission that any of the information it contains constitutes prior art against the present patent application.